This invention relates to the field of mass spectrometry, and provides a method and apparatus for analyzing data obtained from a mass spectrometer.
Mass spectrometers have long been used for performing qualitative analysis of substances. A mass spectrometer can essentially reduce a test sample to a set of ionic components, and displays the mass, and relative abundance, of each such component. The mass spectrometer produces an output that can be represented as a graph showing the mass of each component (for example, on the horizontal axis) and the intensity, or relative abundance, of each component (for example, on the vertical axis). The graph generated by a mass spectrometer is called a “spectrum”.
Examples of the use of mass spectrometry in the field of biological science are given in U.S. Pat. Nos. 6,017,693 and 5,538,897, the disclosures of which are incorporated by reference herein.
A major problem in the use of a mass spectrometer is in the analysis of the spectrum generated by the device. Typically, an unknown substance is to be evaluated and compared with the spectrum of a known substance. A simple visual comparison of the spectrum of the unknown substance with a known spectrum is often insufficient and unproductive, as the points of similarity between the spectra are often not apparent to the human observer.
Even numerical methods of comparison of spectra, known in the prior art, have been unsatisfactory. It has been known to calculate correlations between spectra, but such calculations have been cumbersome and impractical.
The present invention provides a computer-based method of analyzing spectra from a mass spectrometer. The method of the present invention enables the user to obtain information about the spectrum of a test sample, even where such information is not intuitively obvious or readily observable.